Dont require Converters for Complex classes that are used as Ids [DATAMONGO-485]

[spring-projects-issues]

Alexander Bätz opened DATAMONGO-485 and commented

We want to store Domain-Objects that use complex classes as ids (every object has a property id that is a complex class) from Hazelcast. see project and projectId for an example.

when we try and call save on the mongo-template with a complete object (with id).

Call:
MongoTemplate.save(object);

Result:

org.springframework.data.mapping.model.MappingException: Cannot use a complex object as a key value.
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeMapInternal(MappingMongoConverter.java:525) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writePropertyInternal(MappingMongoConverter.java:385) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter$3.doWithPersistentProperty(MappingMongoConverter.java:346) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter$3.doWithPersistentProperty(MappingMongoConverter.java:335) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mapping.model.BasicPersistentEntity.doWithProperties(BasicPersistentEntity.java:173) ~[spring-data-commons-core-1.2.1.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeInternal(MappingMongoConverter.java:335) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeInternal(MappingMongoConverter.java:307) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.write(MappingMongoConverter.java:272) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.write(MappingMongoConverter.java:73) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.MongoTemplate.doSave(MongoTemplate.java:718) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:708) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:704) ~[spring-data-mongodb-1.0.2.RELEASE.jar:na]
	at net.bigpoint.globalchat.hazelcast.MongoMapStore.store(MongoMapStore.java:86) [classes/:na]
	at net.bigpoint.globalchat.hazelcast.MongoMapStore.store(MongoMapStore.java:1) [classes/:na]
	at com.hazelcast.impl.concurrentmap.MapStoreWrapper.store(MapStoreWrapper.java:114) [hazelcast-2.1.2.jar:2.1.2]
	at com.hazelcast.impl.ConcurrentMapManager$PutOperationHandler$PutStorer.doMapStoreOperation(ConcurrentMapManager.java:2853) [hazelcast-2.1.2.jar:2.1.2]
	at com.hazelcast.impl.ConcurrentMapManager$AbstractMapStoreOperation.run(ConcurrentMapManager.java:3560) [hazelcast-2.1.2.jar:2.1.2]
	at com.hazelcast.impl.executor.ParallelExecutorService$ParallelExecutorImpl$ExecutionSegment.run(ParallelExecutorService.java:212) [hazelcast-2.1.2.jar:2.1.2]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [na:1.7.0_04]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [na:1.7.0_04]
	at java.lang.Thread.run(Thread.java:722) [na:1.7.0_04]
	at com.hazelcast.impl.ExecutorThreadFactory$1.run(ExecutorThreadFactory.java:38) [hazelcast-2.1.2.jar:2.1.2]

---

Attachments:

• Project.java (688 bytes)
• ProjectId.java (320 bytes)

Issue Links:

• DATAMONGO-242 Allow using complex types as Map keys
  ("duplicates")

[spring-projects-issues]

Alexander Bätz commented

i forgot to mention: once we implement and configure a Converter for our id class. everything works. but since we have a lot of id classes this is a lot of boilerplate code

[spring-projects-issues]

Oliver Drotbohm commented

I've added test cases in the 1.0.x and 1.1.x branch that shows complex ids are supported in general. Would you mind coming up with a test case showing the actual error?

The stacktrace seems to indicate you're trying to persist a Map by some means and have a complex type as key, which we currently don't support yet (see DATAMONGO-242) for details

[spring-projects-issues]

Carlos Bribiescas commented

Is there any technical reasons that this hasn't been implemented yet? Or just that it's low on the priority list?

I checked out org.springframework.data.mongodb.core.convert.MappingMongoConverter#createMap. I can imagine writing out a map as two parallel lists, one with keys, and one with values. (This is assuming keys and values are convertible) Is there a reason why this wouldn't work?

[spring-projects-issues]

Oliver Drotbohm commented

The summary of the ticket is misleading as I've outlined in my comment above. I didn't change it (or better resolve it as duplicate of DATAMONGO-242) because there was no further feedback by the original reporter yet.

The reason we didn't progress with complex map key is that while writing them is pretty trivial – even despite the fact that there's more than one way to do it – working with those maps is way more complicated than it first seems: query translation has to be adapted, indexing has to be adapted etc. So for now we basically decided not to support it at all rather than supporting it in a half-baked way.

[spring-projects-issues]

Michal Moravcik commented

Hi Oliver,

sorry for posting my question here, but this is the most relevant comment I have found for my problem.

Could you please specify, or point me to some documentation how I can serialize/deserialize my complex key into/from string? In my case I don't need the map key to be stored as complex in MongoDB, it can be easily serialized into String, but in Java code I rather want it as a complex type. Is that possible?

In my Spring Data Rest endpoint it works out of the box with the toString and parse methods